The ADF4158 is a 6.1 GHz, fractional-N frequency synthesizer with modulation and waveform generation capability. It con-tains a 25-bit fixed modulus, allowing subhertz resolution at 6.1 GHz. It consists of a low noise digital phase frequency detector (PFD), a precision charge pump, and a programmable reference divider. There is a sigma-delta (Σ-Δ) based fractional interpolator to allow programmable fractional-N division. The INT and FRAC registers define an overall N-divider as N = INT + (FRAC/225).
The ADF4158 can be used to implement frequency shift keying (FSK) and phase shift keying (PSK) modulation. There are also a number of frequency sweep modes available, which generate various waveforms in the frequency domain, for example, sawtooth and triangular waveforms. The ADF4158 features cycle slip reduction circuitry, which leads to faster lock times, without the need for modifications to the loop filter.
Control of all on-chip registers is via a simple 3-wire inter- face. The device operates with a power supply ranging from 2.7 V to 3.3 V and can be powered down when not in use.
Applications
- FMCW radar
- Communications test equipment
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